Re: [Digital BW] "Encapsulation"
2003-12-23 by Ernst Dinkla
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From: "J Vee" <j.vee@...> To: <DigitalBlackandWhiteThePrint@yahoogroups.com> Sent: Tuesday, December 23, 2003 6:33 PM Subject: [Digital BW] "Encapsulation" >Is there evidence that gelatin "encapsulation" of the print is not consistent with extended longevity? The reason I ask is that, since I am also a traditional "Carbon" printer, I wonder if there is something to be learned from those techniques which have resulted in well preserved prints from at least the late 1800's. One feature is that receiving paper (paper to receive the transferred pigment image which is a suspension of pigment in gelatin) is floated (basically immersed) in a gelatin suspension. After receiving the image, this "sandwich" is made permanent by soaking in formalin solution. I have left out a lot. This, I believe, cross links the protein molecules of the gelatin. These images are about as permanent (including the 3 & 4 color ones) that have been made. As a pathologist I can attest to the preserving effect of formalin. A word to the wise -- it's a possible carcinogen, but that concern has probably been overblown. Any tests been done on digital prints? Any thoughts? J Vee< The Carbon B&W print consisted of a carbon pigment + in your description a hardened gelatine on a rag paper usually. The inkjet prints made with carbon pigment inks are often not printed on gelatine coated paper, the paper often isn't a rag paper. The sizing of the paper may however contain gelatine or PVA. The gelatine or PVA coated papers (swellable) are more compatible with dye inks. Hardening that combination will then not be much different from hardened analogue photographic prints. If the dye and gelatine allow a waterbased process. There may be a possibility to apply a gelatine coating on the microporeus paper coatings usually used with pigment inks and then hardening with formaline afterwards. The waterfastness is less of a problem with pigment inks and microporeus coatings. Risks could be a less flexible toplayer or one that gets less flexible in time and possible yellowing in time of the hardened layer. Gloss will be lowered by the hardening. All the B&W films that I have developed in the 70's were treated with a formaline hardening at the end of process. That was a good decision as I still can use them despite a not so archival storage in time. If I remember it correctly the PH grade of teh emulsion had to be correct before the formaline was used, wonder whether that can be met in digital prints. I have seen an article in a magazine mentioning the use of waterglass as a sealing for prints that had to be used outdoors. More to increase the waterfastness. Could be a way to seal matte prints. Ernst